Translator Disclaimer
1 June 2009 Flower-Inhabiting Frankliniella Thrips (Thysanoptera: Thripidae), Pesticides, and Fusarium Hardlock in Cotton
Author Affiliations +
Abstract

Cotton hardlock caused by Fusarium verticillioides (Sacc. Nirenberg) can reduce cotton, Gossypium hirsutum L., yields >70% in the southeastern United States. The spores infect flowers on the day of pollination, resulting in hardlock, which is the failure of the fiber to fluff as the boll opens at maturity. Frankliniella spp. Thrips (Thysanoptera: Thripidae) inhabiting the flowers are hypothesized to increase hardlock by spreading the conidia or by creating entranceways for the germinating Fusarium conidia. Experiments were conducted at Marianna and Quincy in Florida in 2006 and 2007 to determine whether there was a relationship between the number of adult and larval thrips inhabiting the flowers of cotton and the incidence of cotton hardlock. Frankliniella tritici (Fitch) was >98% of the adult thrips in the samples at both locations each year. The adults of Frankliniella bispinosa (Morgan) and Frankliniella occidentalis (Pergande) also were collected. There were no significant regression relationships between weekly mean densities of thrips in the flowers and the incidence of cotton hardlock at harvest in any of the experiments. Additional experiments were conducted at each location in 2006 and 2007 to determine whether weekly applications during flowering of the insecticide lambda-cyhalothrin, the fungicide thiophanate methyl, and the combination of the two reduced the incidence of cotton hardlock at harvest. Applications of the insecticide significantly reduced the numbers of adult F. tritici, the number of thrips larvae, and the incidence of hardlock at harvest. Applications of the insecticide were as affective as applications of the insecticide plus fungicide. In one experiment, applications of the fungicide reduced the incidence of hardlock at harvest. Applications of the insecticide usually significantly increased the number of adult F. occidentalis. None of the pesticide treatments significantly affected the numbers of the key thrips predator Orius insidiosus (Say). We conclude that insecticidal control of the adults and larvae of F. tritici during flowering reduced the incidence of cotton hardlock. However, there were no significant regression relationships between the incidence of cotton hardlock at harvest and the number of thrips in the flowers.

© 2009 Entomological Society of America
Enoch A. Osekre, David L. Wright, James J. Marois, and Joe Funderburk "Flower-Inhabiting Frankliniella Thrips (Thysanoptera: Thripidae), Pesticides, and Fusarium Hardlock in Cotton," Journal of Economic Entomology 102(3), 887-896, (1 June 2009). https://doi.org/10.1603/029.102.0305
Received: 30 July 2008; Accepted: 1 January 2009; Published: 1 June 2009
JOURNAL ARTICLE
10 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top